Yeah... i can see that...my software is the last one
Nice feature.
Be carefull running behind Robert Luongo..if you race in a circle..if he was faster..then he will be behind you...a possible crash, as he may be faster, can be dangerous, will hurt some folks, others will come out.
We love football...we run behind he ball..we do not want balls running behind us..reason why the game use only a single ball.
Ahahahah..that was deep.
regards,
Carlos
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Despite all these features, i would be much more happy, if i could have, an artistic view, we could post in this forum, as an opened image, and/or a pdf file.
I hope these new features drives you happy... at least you will feel good.
........................................................................................................
Nice feature.
Be carefull running behind Robert Luongo..if you race in a circle..if he was faster..then he will be behind you...a possible crash, as he may be faster, can be dangerous, will hurt some folks, others will come out.
We love football...we run behind he ball..we do not want balls running behind us..reason why the game use only a single ball.
Ahahahah..that was deep.
regards,
Carlos
........................................................................................................
Despite all these features, i would be much more happy, if i could have, an artistic view, we could post in this forum, as an opened image, and/or a pdf file.
I hope these new features drives you happy... at least you will feel good.
........................................................................................................
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I prefer to SIT behind Roberto Luongo -- in the audience. With a beer, and my lady. Hockey, women, beer... it's an unbeatable combination. 😉
..Todd
Attachments
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it took me a while to find.
Go to: View - Navigation panels - Layers.
Then click each of the layers off.
Finally click the wanted layer back on.
Misc is nice - shows the two links beautifully.
Go to: View - Navigation panels - Layers.
Then click each of the layers off.
Finally click the wanted layer back on.
Misc is nice - shows the two links beautifully.
Do I detect a bit of sarcasm there? What about the fuses, connectors, output coil and bias trimmer?
..Todd
pcb service???
hi does anyone offer the pcbs for sale i know that this is a diy project but it be less hassle for me to buy these off the diyers. manifacturer company ask for ridiculous prices. I do not mind etching my own but i never done etching before and i do not know what is needed for etching will thankful if anyone can provide some website that offers pcb etchin kit suitable for producing this project (must accept paypal).
hi does anyone offer the pcbs for sale i know that this is a diy project but it be less hassle for me to buy these off the diyers. manifacturer company ask for ridiculous prices. I do not mind etching my own but i never done etching before and i do not know what is needed for etching will thankful if anyone can provide some website that offers pcb etchin kit suitable for producing this project (must accept paypal).
carlos,in your DX blame ES amplifier ,why have you chosen to use a bootstrap instead of a current source with transistor for the vas stage??
I love boostrap sound....now i am creating the Fokker..i am not satisfied
with CCS in the place of boostrap...well..this is a very long (and old) story.
You can install a CCS if you believe it can be better for your taste...it is up to you.
Knowing what bootstrap does to sound reproduction..knowing how it operates...an analogy to the boot strap...the holder you use to pull you feet inside the boot..then you will love it too.
You see...Papa Nelson Pass is now using..he knows what produces good sound...his last design uses bootstrapp..also other important guys, alike John Lindsey (Lindsley) Hood have used.
There are prejudices..people say it is old..but they do not even listen to one and other.... too much lazy to produce an amplifier having a switchable bootstrapp and a CCS..both of them adjusted to the same current...and them to compare...they have never made that..and go repeating, without knowing, alike pirate parrot, that bootstrap is not so good as CCS.
regards,
Carlos
with CCS in the place of boostrap...well..this is a very long (and old) story.
You can install a CCS if you believe it can be better for your taste...it is up to you.
Knowing what bootstrap does to sound reproduction..knowing how it operates...an analogy to the boot strap...the holder you use to pull you feet inside the boot..then you will love it too.
You see...Papa Nelson Pass is now using..he knows what produces good sound...his last design uses bootstrapp..also other important guys, alike John Lindsey (Lindsley) Hood have used.
There are prejudices..people say it is old..but they do not even listen to one and other.... too much lazy to produce an amplifier having a switchable bootstrapp and a CCS..both of them adjusted to the same current...and them to compare...they have never made that..and go repeating, without knowing, alike pirate parrot, that bootstrap is not so good as CCS.
regards,
Carlos
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Bootstrap is superior to a resistor load but inferior to a current source or a complimentary VAS. It was widely used when the bootstrap capacitor and power resistors were way less expensive than CCS transistors (1970s). Now it's the opposite.
- Clipping behaviour is worse and harder to control. The bootstrap allows one of the driver transistors to saturate deeply, which results in sticking to one of the rails (and from time to time dozens of pairs of shorted output devices). This is one of the main pitfalls in Carlos circuits. In any good amplifier output stage should never be allowed to saturate.
- This in fact results in asymmetric waveform clipping (and thus subsonics will be produced when clipping). Output goes several volts closer to one rail than to the other. Another pitfall in Carlos circuits.
- The current provided by the bootstrap includes all the phase lag of all the output stage (with base stopper resistors, etc). This results in worse phase margin for the whole amplifier. Less negative feedback can be used above 1Khz resulting in higher distortion and worse tonal unbalance due to rising amplifier output impedance.
- The current provided by the bootstrap includes all the distortion from the output of the amplifier (crossover glitches, etc.) which is fed back into the output stage with some delay.
- A loud thump is produced at turn off. This is unless the input stage supply rails are isolated with diodes from main rails, and enough storage capacitance is added after the diodes to force input stage to turn off only after the bootstrap capacitor has discharged.
- The amplifier can't be muted easily because turning off the input stage causes the output to go close to one of the rails. The bootstrap would have to be turned off too.
- The current through the Vbe multiplier is not controlled, it's strictly proportional to supply rail voltage. Since Vbe multiplier DC output impedance is not low, VAS bias current has a direct impact on output stage bias current. This means that if you adjust bias with +/-40V rails, the amplifier will be underbiased at +/-30V or +/-20V. And if you adjust bias with +/-20V, the amplifier will be overbiased with +/-30V and will usually blow with +/-40V (with everything else being OK). One more pitfall that routinely brings headaches to Carlos.
My philosophy is to design amplifiers whose internal bias currents don't depend at all on supply voltages (within a reasonable margin). This is mostly the philosophy in use today. Expending a few extra dollars in some transistors to get all currents well controlled is worth the effort, not to mention all the measurable improvements in amplifier output signal quality.
But consider that some people fear the complexity of using more transistors because they already have trouble getting the circuit right with a few ones. If you can't get a current source stable (no oscillations) or a complimentary VAS right, then bootstrapped VAS is for you 😉 It's not as "clean" but it's really fool proof 😀
All these notes come from experience, it's not preconceived belief.
- Clipping behaviour is worse and harder to control. The bootstrap allows one of the driver transistors to saturate deeply, which results in sticking to one of the rails (and from time to time dozens of pairs of shorted output devices). This is one of the main pitfalls in Carlos circuits. In any good amplifier output stage should never be allowed to saturate.
- This in fact results in asymmetric waveform clipping (and thus subsonics will be produced when clipping). Output goes several volts closer to one rail than to the other. Another pitfall in Carlos circuits.
- The current provided by the bootstrap includes all the phase lag of all the output stage (with base stopper resistors, etc). This results in worse phase margin for the whole amplifier. Less negative feedback can be used above 1Khz resulting in higher distortion and worse tonal unbalance due to rising amplifier output impedance.
- The current provided by the bootstrap includes all the distortion from the output of the amplifier (crossover glitches, etc.) which is fed back into the output stage with some delay.
- A loud thump is produced at turn off. This is unless the input stage supply rails are isolated with diodes from main rails, and enough storage capacitance is added after the diodes to force input stage to turn off only after the bootstrap capacitor has discharged.
- The amplifier can't be muted easily because turning off the input stage causes the output to go close to one of the rails. The bootstrap would have to be turned off too.
- The current through the Vbe multiplier is not controlled, it's strictly proportional to supply rail voltage. Since Vbe multiplier DC output impedance is not low, VAS bias current has a direct impact on output stage bias current. This means that if you adjust bias with +/-40V rails, the amplifier will be underbiased at +/-30V or +/-20V. And if you adjust bias with +/-20V, the amplifier will be overbiased with +/-30V and will usually blow with +/-40V (with everything else being OK). One more pitfall that routinely brings headaches to Carlos.
My philosophy is to design amplifiers whose internal bias currents don't depend at all on supply voltages (within a reasonable margin). This is mostly the philosophy in use today. Expending a few extra dollars in some transistors to get all currents well controlled is worth the effort, not to mention all the measurable improvements in amplifier output signal quality.
But consider that some people fear the complexity of using more transistors because they already have trouble getting the circuit right with a few ones. If you can't get a current source stable (no oscillations) or a complimentary VAS right, then bootstrapped VAS is for you 😉 It's not as "clean" but it's really fool proof 😀
All these notes come from experience, it's not preconceived belief.
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Eva, as usual bombing people..using the mask wanna help
Wanna criticize my dear...take a chair.
But be aware... eveybody is reading ...also moderators.
regards,
Carlos
Wanna criticize my dear...take a chair.
But be aware... eveybody is reading ...also moderators.
regards,
Carlos
Not refering to anyone elses design but in general, I agree. Furthermore, designing a circuit so that operation including bias is not based on the individual device parameters or tolerances that vary from component to component. Very rarely does my circuits require less than 5% resistors. IMO, you should be able to take any part out and replace it with a random pick from the same type parts bag not necessarily from the same production run and have the same operation results from the circuit. (Concidering matched components act as one.)
This improves reliability greatly.🙂
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You do not need to build CBS... search something better to you
Why are you wasting your time with this amplifier?
regards,
Carlos
Why are you wasting your time with this amplifier?
regards,
Carlos
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